1. Field of the Invention
This invention relates to a beam stop for moderate to high power lasers that indicates the presence and strength of the laser beam.
2. Description of the Prior Art
There are three common problems in the laser laboratory. First, it is often necessary to block a laser beam in order to adjust another part of the instrument or experiment. It is typically more convenient to block the beam than to shut off the laser. While devices are offered or can be improvised for this purpose, they often produce specular reflections that are an eye hazard, particularly with invisible (e.g. UV or IR) laser beams. It is desirable that beam blocks reflect none (and thus absorb all) of the incident radiation. While some lasers have built-in beam blocks, these can be inconvenient to reach. For higher energy lasers, the block must also absorb a considerable amount of energy in a small volume.
Second, it is often useful to use a photoluminescent laser target to judge the mode structure (shape) and strength of the laser beam. While instruments are available to do this, they often are less convenient and no more accurate for the usual minor adjustments that are performed to optimize the laser output. Unfortunately, the fluorescent cards commonly used for this purpose produce a very small, bright spot when hit by the beam, which makes it difficult to judge the strength of the beam, especially in a darkened room. Moreover, these fluorescent cards are bleached or destroyed by stronger laser beams.
Third, laser beams from visible lasers are difficult to see from the side and pose a safety hazard, unless a scatterer in present, such as dust in the air. Unfortunately, lasers are typically used in clean environments, and beams strong enough to cause eye damage from specular reflection can be impossible to see. With UV and IR laser beams, the beam can be very dangerous without any visible effect.
Thus it would be useful to have a device that can serve as a beam block and indicate the strength, direction, and position of a laser beam, and entirely absorb the energy incident upon it from the laser.